21915263 has 2 divisors, whose sum is σ = 21915264. Its totient is φ = 21915262.

The previous prime is 21915259. The next prime is 21915277. The reversal of 21915263 is 36251912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21915263 - 2² = 21915259 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21915203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10957631 + 10957632.

It is an arithmetic number, because the mean of its divisors is an integer number (10957632).

Almost surely, 2^21915263 is an apocalyptic number.

21915263 is a deficient number, since it is larger than the sum of its proper divisors (1).

21915263 is an equidigital number, since it uses as much as digits as its factorization.

21915263 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 29.

The square root of 21915263 is about 4681.3740504258. The cubic root of 21915263 is about 279.8437180596.

The spelling of 21915263 in words is "twenty-one million, nine hundred fifteen thousand, two hundred sixty-three".